This invention relates to a method of producing imide bond-containing resins and flame retardants comprising said resins.
Recent years have seen a constant and remarkable expansion of the field of applications of plastics. The characteristics required of plastic materials have become diversified accordingly. In particular, fire and flame resistance is a characteristic required of plastics to be used in a very great number of applications, for example as building materials, materials for electric appliances, and automobile parts, among others. The role of flame retardants, which provide plastics with fire or flame resistance, is very important.
Such flame retardants are required not only to be able to provide plastics with good fire or flame resistance without impairing the intrinsic physical properties of the plastics but also to have, by themselves, good heat resistance and weather resistance.
Under such circumstances, certain flame retardants comprising imide bond-containing resins have attracted recent attention but are not fully satisfactory as yet.